Study On The Low Complexity Detection Of Generalized Spatial Modulation

Spatial modulation(SM)has been recognized as a promising MIMO transmission technology which can effectively reduce the number of radio frequency(RF)chain to develop energy-efficient,low-complexity solutions that satisfy target throughput requirements in future mobile networks.Generalized spatial modulation(GSM)is a generalization of SM.Comparing with SM,GSM has more than one active transmit antenna in every symbol time,which promotes the transmission rate while making the signal detection more complicate.Based on the operational principle of SM,the paper summarizes and analyzes two main merits of SM: the simplification of RF and the promotion of spectral efficiency.Meanwhile,the existing problem and future of SM is discussed.Aim for the low complexity detection in overdetermined system,the general steps of lattice reduction(LR)aided linear detection for GSM is given.However,the elements in transmit vector should be consecutive integers,which cannot be satisfied for GSM modulated by general QAM/PSK.In order to solve the compatible problem in application of LR-aid linear detection in GSM,a special 8-QAM constellation is proposed.Then,the paper proves that LR-aided linear equalizers collect the same diversity order as that exploited by the ML detector under Rayleigh fading channels and proves it by simulation.By simulation on BER performance,the superior of the proposed 8-QAM over traditional 4-QAM and 8-QAM under Rayleigh fading channel is testified.Moreover,the scheme obtains the full receive diversity under correlated channel.In addition,the complexity lattice reduction brings is negligible under the transmit antenna number constraint in the uplink of GSM.As for the underdetermined system in GSM,based on the enhanced Orthogonal Matching Pursuit(E-OMP)algorithm which applies the signal recover algorithm in compressive sensing(CS),the enhanced Stagewise Orthogonal Matching Pursuit(E-StOMP)algorithm that can reduce the complexity of E-OMP is proposed while the E-StOMP suffers a BER deterioration.Considering the ‘error floor' phenomenon in the E-OMP and E-StOMP algorithm,an Ordered Block Minimum Mean-Squared Error(OB-MMSE)detector based on the OMP algorithm that have a BER superiority in BER performance on OB-MMSE detector while still keep a nearly same complexity as the latter one is given.